PROJECT SUMMARY/ABSTRACT Real-time risk factors for prescription stimulant misuse (PSM) among young adult college students are poorly understood, while the sociodemographic and substance use correlates in this population are better established. The lack of knowledge about real-time antecedents of college student PSM limits the effectiveness of prevention and targeted treatment options to reduce the consequences of such misuse. The long-term goal of the PI is to identify risk factors for PSM, key mediators and moderators of the antecedent-PSM relationship and to evaluate theories that help establish the etiology of PSM. In this application, the overall objectives are to: first, use ecological momentary assessment (EMA) to determine how changes in real-time affect [and affective control] influence PSM episodes and evaluate the effects of distal affect-related variables, such as negative and positive urgency and affective control, on PSM frequency; and second, to evaluate the influences of real-time changes in global perceived stress, perceived academic stress, [self-efficacy] and demands on PSM episodes (using EMA). The first objective comprises Aim 1 and the second captures Aim 2. The variables for the first aim were selected using affect dysregulation models of substance use, and variables for the second were informed by a drug instrumentalization model. Work in college students engaged in PSM and the PI's pilot data indicate that alteration of affect and academic enhancement (i.e., using the stimulant as an instrument to enhance academic performance) are two key PSM motives. The central hypotheses, based on these theories and the pilot data, are that real-time increases in negative affect, global stress, academic stress and demands and decreases in positive affect, [affective control and academic self-efficacy] will precede PSM episodes; also, higher baseline levels of positive and negative urgency and poorer baseline affective control will predict a greater number of PSM episodes in the 21-day EMA period. The rationale for this work is that identification of real-time PSM correlates in an ecologically valid fashion and identification of baseline risk factors for higher PSM frequency will provide clearer targets for behavioral interventions (e.g., emotional regulation strategies) [and potential subgroups of stimulant misusers to target,] limiting the impact of PSM. Evaluation of theoretically-based real-time risk factors for college student PSM, which could inform improvements in interventions, gives this application the potential for a significant contribution to the substance use research and treatment fields. Furthermore, the research proposed here is innovative because it represents a substantial departure from the current PSM research by applying methodology (i.e., EMA) to investigate real-time PSM correlates, guided by theories with strong support in other forms of substance use. Rapid dissemination of the knowledge derived from this work has the potential to improve the few current intervention options and aid the development of new and maximally effective interventions to reduce PSM in young adult college students, all of which is consistent with the mission of NIDA.